Adaptive query processor for query systems with limited capabilities

ABSTRACT

A query processor determines if an initial query results in a query system having a search engine coupled to a database to identify a limited maximum number of records deliverable by the query system. This limitation is indicative of an incomplete result because records are includable in the query may not be included in the result. In response the query processor generates a plurality of queries that cause the query system to generate results that identify less than the maximum number. The results of the plurality of queries are combined as a response to the initial query. Duplicate records caused by any overlap in the plurality of queries may be eliminated from the combination. Determining a median value of a query range that causes the query system to deliver the maximum number of records may be utilized in the generation of the plurality of queries.

BACKGROUND

This disclosure broadly relates to the field of query processing, andmore particularly to the field of adapting a query to enhance resultsproduced by a limited capability query system.

Systems for searching databases with queries has grown with the growthof the Internet and the advent of cloud based services. A query may begenerated by a client user and sent to any of several query systems by aquery processor. The results of the query are then returned to theclient user. Each query system may have a database and a search enginefor performing a search based upon the query. A query processor mayreceive a query from a query generator and send the query to one or morequery systems. Query systems are not uniform or standardized and havevarying limitations depending upon the database and the search engineassociated with the database. The limitations of various query systemsmay result in a return of incomplete results by the query system.

SUMMARY

One or more embodiments of the invention include a method, processor andcomputer program product for receiving an initial query, determiningthat the initial query causes a query system to identify a maximumnumber of records deliverable by the query system, and generating aplurality of queries based upon the initial query, each of the pluralityof queries causing the query system to identify less than the maximumnumber of records deliverable by the query system.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying figures where like reference numerals refer toidentical or functionally similar elements throughout the separateviews, and which together with the detailed description below areincorporated in and form part of the specification, serve to furtherillustrate various embodiments and to explain various principles andadvantages all in accordance with the present disclosure, in which:

FIG. 1 depicts a cloud computing node according to an embodiment of thepresent invention;

FIG. 2 depicts a cloud computing environment according to an embodimentof the present invention;

FIG. 3 depicts abstraction model layers according to an embodiment ofthe present invention;

FIG. 4 depicts a block diagram of a query processor for querying querysystems with limited capabilities;

FIG. 5 depicts an example flow diagram of a process operating in a queryprocessor for querying systems with limited capabilities;

FIG. 6 depicts an example flow diagram of a process for modifying aquery having a range; and

FIG. 7 depicts an example flow diagram of a process for determining amedian key value of a current query.

DETAILED DESCRIPTION

In the following discussion, details are provided to help thoroughlyunderstand the present disclosure. However, it is apparent to those ofordinary skill in the art that even though there may be no such details,the understanding of the present disclosure would not be influenced. Inaddition, it should be further appreciated that any specific terms orapplications used herein are only for the convenience of description,and thus the present disclosure should not be limited to only use in anyspecific terms or applications represented and/or implied by such terms.

I. Cloud Computing Environment

It is understood in advance that although this disclosure includes adetailed description on cloud computing, implementation of the teachingsrecited herein are not limited to a cloud computing environment. Rather,embodiments of the present invention are capable of being implemented inconjunction with any other type of computing environment now known orlater developed.

Cloud computing is a model of service delivery for enabling convenient,on-demand network access to a shared pool of configurable computingresources (e.g. networks, network bandwidth, servers, processing,memory, storage, applications, virtual machines, and services) that canbe rapidly provisioned and released with minimal management effort orinteraction with a provider of the service. This cloud model may includeat least five characteristics, at least three service models, and atleast four deployment models.

Characteristics are as follows:

On-demand self-service: a cloud consumer can unilaterally provisioncomputing capabilities, such as server time and network storage, asneeded automatically without requiring human interaction with theservice's provider.

Broad network access: capabilities are available over a network andaccessed through standard mechanisms that promote use by heterogeneousthin or thick client platforms (e.g., mobile phones, laptops, and PDAs).

Resource pooling: the provider's computing resources are pooled to servemultiple consumers using a multi-tenant model, with different physicaland virtual resources dynamically assigned and reassigned according todemand. There is a sense of location independence in that the consumergenerally has no control or knowledge over the exact location of theprovided resources but may be able to specify location at a higher levelof abstraction (e.g., country, state, or datacenter).

Rapid elasticity: capabilities can be rapidly and elasticallyprovisioned, in some cases automatically, to quickly scale out andrapidly released to quickly scale in. To the consumer, the capabilitiesavailable for provisioning often appear to be unlimited and can bepurchased in any quantity at any time.

Measured service: cloud systems automatically control and optimizeresource use by leveraging a metering capability at some level ofabstraction appropriate to the type of service (e.g., storage,processing, bandwidth, and active user accounts). Resource usage can bemonitored, controlled, and reported providing transparency for both theprovider and consumer of the utilized service.

Service Models are as follows:

Software as a Service (SaaS): the capability provided to the consumer isto use the provider's applications running on a cloud infrastructure.The applications are accessible from various client devices through athin client interface such as a web browser (e.g., web-based email). Theconsumer does not manage or control the underlying cloud infrastructureincluding network, servers, operating systems, storage, or evenindividual application capabilities, with the possible exception oflimited user-specific application configuration settings.

Platform as a Service (PaaS): the capability provided to the consumer isto deploy onto the cloud infrastructure consumer-created or acquiredapplications created using programming languages and tools supported bythe provider. The consumer does not manage or control the underlyingcloud infrastructure including networks, servers, operating systems, orstorage, but has control over the deployed applications and possiblyapplication hosting environment configurations.

Infrastructure as a Service (IaaS): the capability provided to theconsumer is to provision processing, storage, networks, and otherfundamental computing resources where the consumer is able to deploy andrun arbitrary software, which can include operating systems andapplications. The consumer does not manage or control the underlyingcloud infrastructure but has control over operating systems, storage,deployed applications, and possibly limited control of select networkingcomponents (e.g., host firewalls).

Deployment Models are as follows:

Private cloud: the cloud infrastructure is operated solely for anorganization. It may be managed by the organization or a third party andmay exist on-premises or off-premises.

Community cloud: the cloud infrastructure is shared by severalorganizations and supports a specific community that has shared concerns(e.g., mission, security requirements, policy, and complianceconsiderations). It may be managed by the organizations or a third partyand may exist on-premises or off-premises.

Public cloud: the cloud infrastructure is made available to the generalpublic or a large industry group and is owned by an organization sellingcloud services.

Hybrid cloud: the cloud infrastructure is a composition of two or moreclouds (private, community, or public) that remain unique entities butare bound together by standardized or proprietary technology thatenables data and application portability (e.g., cloud bursting for loadbalancing between clouds).

A cloud computing environment is service oriented with a focus onstatelessness, low coupling, modularity, and semantic interoperability.At the heart of cloud computing is an infrastructure comprising anetwork of interconnected nodes.

Referring now to FIG. 1, a schematic of an example of a cloud computingnode is shown. Cloud computing node 10 is only one example of a suitablecloud computing node and is not intended to suggest any limitation as tothe scope of use or functionality of embodiments of the inventiondescribed herein. Regardless, cloud computing node 10 is capable ofbeing implemented and/or performing any of the functionality set forthhereinabove.

In cloud computing node 10 there is a computer system/server 12, whichis operational with numerous other general purpose or special purposecomputing system environments or configurations. Examples of well-knowncomputing systems, environments, and/or configurations that may besuitable for use with computer system/server 12 include, but are notlimited to, personal computer systems, server computer systems, thinclients, thick clients, handheld or laptop devices, multiprocessorsystems, microprocessor-based systems, set top boxes, programmableconsumer electronics, network PCs, minicomputer systems, mainframecomputer systems, and distributed cloud computing environments thatinclude any of the above systems or devices, and the like.

Computer system/server 12 may be described in the general context ofcomputer system executable instructions, such as program modules, beingexecuted by a computer system. Generally, program modules may includeroutines, programs, objects, components, logic, data structures, and soon that perform particular tasks or implement particular abstract datatypes. Computer system/server 12 may be practiced in distributed cloudcomputing environments where tasks are performed by remote processingdevices that are linked through a communications network. In adistributed cloud computing environment, program modules may be locatedin both local and remote computer system storage media including memorystorage devices.

As shown in FIG. 1, computer system/server 12 in cloud computing node 10is shown in the form of a general-purpose computing device. Thecomponents of computer system/server 12 may include, but are not limitedto, one or more processors or processing units 16, a system memory 28,and a bus 18 that couples various system components including systemmemory 28 to processor 16.

Bus 18 represents one or more of any of several types of bus structures,including a memory bus or memory controller, a peripheral bus, anaccelerated graphics port, and a processor or local bus using any of avariety of bus architectures. By way of example, and not limitation,such architectures include Industry Standard Architecture (ISA) bus,Micro Channel Architecture (MCA) bus, Enhanced ISA (EISA) bus, VideoElectronics Standards Association (VESA) local bus, and PeripheralComponent Interconnect (PCI) bus.

Computer system/server 12 typically includes a variety of computersystem readable media. Such media may be any available media that isaccessible by computer system/server 12, and it includes both volatileand non-volatile media, removable and non-removable media.

System memory 28 can include computer system readable media in the formof volatile memory, such as random access memory (RAM) 30 and/or cachememory 32. Computer system/server 12 may further include otherremovable/non-removable, volatile/non-volatile computer system storagemedia. By way of example only, storage system 34 can be provided forreading from and writing to a non-removable, non-volatile magnetic media(not shown and typically called a “hard drive”). Although not shown, amagnetic disk drive for reading from and writing to a removable,non-volatile magnetic disk (e.g., a “floppy disk”), and an optical diskdrive for reading from or writing to a removable, non-volatile opticaldisk such as a CD-ROM, DVD-ROM or other optical media can be provided.In such instances, each can be connected to bus 18 by one or more datamedia interfaces. As will be further depicted and described below,memory 28 may include at least one program product having a set (e.g.,at least one) of program modules that are configured to carry out thefunctions of embodiments of the invention.

Program/utility 40, having a set (at least one) of program modules 42,may be stored in memory 28 by way of example, and not limitation, aswell as an operating system, one or more application programs, otherprogram modules, and program data. Each of the operating system, one ormore application programs, other program modules, and program data orsome combination thereof, may include an implementation of a networkingenvironment. Program modules 42 generally carry out the functions and/ormethodologies of embodiments of the invention as described herein.

Computer system/server 12 may also communicate with one or more externaldevices 14 such as a keyboard, a pointing device, a display 24, etc.;one or more devices that enable a user to interact with computersystem/server 12; and/or any devices (e.g., network card, modem, etc.)that enable computer system/server 12 to communicate with one or moreother computing devices. Such communication can occur via Input/Output(I/O) interfaces 22. Still yet, computer system/server 12 cancommunicate with one or more networks such as a local area network(LAN), a general wide area network (WAN), and/or a public network (e.g.,the Internet) via network adapter 20. As depicted, network adapter 20communicates with the other components of computer system/server 12 viabus 18. It should be understood that although not shown, other hardwareand/or software components could be used in conjunction with computersystem/server 12. Examples, include, but are not limited to: microcode,device drivers, redundant processing units, external disk drive arrays,RAID systems, tape drives, and data archival storage systems, etc.

Referring now to FIG. 2, illustrative cloud computing environment 50 isdepicted. As shown, cloud computing environment 50 comprises one or morecloud computing nodes 10 with which local computing devices used bycloud consumers, such as, for example, personal digital assistant (PDA)or cellular telephone 54A, desktop computer 54B, laptop computer 54C,and/or automobile computer system 54N may communicate. Nodes 10 maycommunicate with one another. They may be grouped (not shown) physicallyor virtually, in one or more networks, such as Private, Community,Public, or Hybrid clouds as described hereinabove, or a combinationthereof. This allows cloud computing environment 50 to offerinfrastructure, platforms and/or software as services for which a cloudconsumer does not need to maintain resources on a local computingdevice. It is understood that the types of computing devices 54A-N shownin FIG. 2 are intended to be illustrative only and that computing nodes10 and cloud computing environment 50 can communicate with any type ofcomputerized device over any type of network and/or network addressableconnection (e.g., using a web browser).

Referring now to FIG. 3, a set of functional abstraction layers providedby cloud computing environment 50 (FIG. 2) is shown. It should beunderstood in advance that the components, layers, and functions shownin FIG. 3 are intended to be illustrative only and embodiments of theinvention are not limited thereto. As depicted, the following layers andcorresponding functions are provided:

Hardware and software layer 60 includes hardware and softwarecomponents. Examples of hardware components include mainframes, in oneexample IBM® zSeries® systems; RISC (Reduced Instruction Set Computer)architecture based servers, in one example IBM pSeries® systems; IBMxSeries® systems; IBM BladeCenter® systems; storage devices; networksand networking components. Examples of software components includenetwork application server software, in one example IBM WebSphere®application server software; and database software, in one example IBMDB2® database software. (IBM, zSeries, pSeries, xSeries, BladeCenter,WebSphere, and DB2 are trademarks of International Business MachinesCorporation registered in many jurisdictions worldwide).

Virtualization layer 62 provides an abstraction layer from which thefollowing examples of virtual entities may be provided: virtual servers;virtual storage; virtual networks, including virtual private networks;virtual applications and operating systems; and virtual clients.

In one example, management layer 64 may provide the functions describedbelow. Resource provisioning provides dynamic procurement of computingresources and other resources that are utilized to perform tasks withinthe cloud computing environment. Metering and Pricing provide costtracking as resources are utilized within the cloud computingenvironment, and billing or invoicing for consumption of theseresources. In one example, these resources may comprise applicationsoftware licenses. Security provides identity verification for cloudconsumers and tasks, as well as protection for data and other resources.User portal provides access to the cloud computing environment forconsumers and system administrators. Service level management providescloud computing resource allocation and management such that requiredservice levels are met. Service Level Agreement (SLA) planning andfulfillment provide pre-arrangement for, and procurement of, cloudcomputing resources for which a future requirement is anticipated inaccordance with an SLA.

Workloads layer 66 provides examples of functionality for which thecloud computing environment may be utilized. Examples of workloads andfunctions which may be provided from this layer include: mapping andnavigation; software development and lifecycle management; virtualclassroom education delivery; data analytics processing; transactionprocessing; and query processing 70.

II. Query Processing

The advent of the Cloud computing environment, Big Data and Analyticshas led to the integration of many new sources of data, not all of whichwere initially conceived as data sources with features supportingsophisticated information querying and retrieval. Certain query systemsmay appears as nodes 10 in the cloud computing environment 50 andprovide data available for querying from queries generated by localcomputing devices 54A-N. But these systems sometimes may not have robustquery processing capabilities along the lines of structured databaseswith mature query and transaction processing languages. For example aquery system may have a data store with items that may be queried by arange of key values but may have limitations. Namely, the number ofresponse records returned may have a fixed limit and the respondentrecords are not sorted. If the query results in more records than thelimit and the records are not sorted the requesting client likely willreceive an incomplete and random selection of records that meet thequery condition but it is not possible for the client to determine ifthe records constitute a contiguous set or if there are missing records,and if so, which records are missing. If the client assumes the resultset is contiguous and issues another query using the highest key valuefrom the previous result set then significant amounts of data may bemissing. The inventor has discovered an approach that provides completesearch results even though the query system may have the aforesaidlimitation by enhancing the operation of the query processor 70.

In operation, the client implements an adaptive query process asfollows:

1. The client constructs a query with desired starting and ending keyvalues.

2. The client submits the query and receives a set of result records ora list of key values representing the result records.

3. If the result set has a number of records equal to the result limitthen the results are not used. The following steps are repeated until aquery result contains a number of records less than the limit

-   -   a. The ending key value from the previous query is pushed on a        stack for later use.    -   b. A new query is constructed with the same starting key value        and a new ending key value computed by finding the median value        of the keys found in a sample of the current result set.    -   c. Submit the new query.

4. When a query result set contain a number of records less than thelimit, those records can be processed and the next query constructedusing the highest key value from this result set as the starting keyvalue and an ending key value that is popped off the top of the stack.Using this previously computed ending key greatly reduces the overheadin computing key values for subsequent queries.

5. Repeat steps 2 through 4 until no more records are returned.

The computation in step 3b. can be intensive in both computer time andmemory space requirements. Computing the median key value from a set ofvalues may be accomplished with at least a partial sorting of thosekeys. Instead a sample of the keys are selected and sorting algorithmknown to be efficient for the data type of the key is used to find themedian key value of the sample set. In experiments it has beendetermined that sampling one record in ten produced a reasonable medianvalue for keys that were substantially uniformly distributed. For keysthat tend to form clusters of values, sampling more records may producebetter results at modest increase in intensity. In the currentimplementation it was experimentally found that issuing a query andreceiving the count of resulting records is a less intensive operation.Retrieving the key values of the result set also did not add significantcomputer time. The more intensive operation was in retrieving the datarecords associated with those result keys. This enhancement allows thequery adaption algorithm to be used without a substantial increase inintensity.

Note that if the data store allows multiple records to have the same keyvalue the query algorithm may be enhanced. On each iteration all of therecords with a key value that is the same as the highest key value foundin a successful query, that is one that retrieved fewer than the limitnumber of records, are saved. The next query will use this highest keyvalue as the starting key value and may find one or more records thatwere returned in the previous iteration. Such matches indicate duplicateresults which are eliminated. If the data store does not permitduplicate values for the query key then this elimination is notnecessary.

FIG. 4 depicts a block diagram of a query processor for querying querysystems with limited capabilities. Client queries are received from aninitial query generator 402 which may correspond to any of the localcomputing devices 54A-N of FIG. 2. An initial query is received by queryprocessor 404 which in one example may correspond to cloud based queryprocess 70 of FIG. 3. In other examples the query processor may exist inother places such as a query extension operating on local computingdevices 54A-N, or operate on another network node 10, including querysystem 406. Query system 406 includes a data store or a database and asearch engine and may be one of several query systems coupled to queryprocessor 404.

The query processor 404 comprises a query receiver 410 receiving aninitial query from the initial query generator 402 and a querytransmitter 412 coupled to the query system 406. In this example, thequery system has a maximum number of records deliverable by the querysystem. The query transmitter transmits at least one query from thequery processor 404 to the query system 406. The query processor alsoincludes a results receiver 414 that receives at least one query resultfrom the query system. The result includes a number of recordsidentified by the query. A maximum record determiner 416 determines ifthe initial query causes the query system to identify the maximum numberof records identifiable by the query system. In this case, the resultsof the query will be not be used for the aforementioned reasons.

In the event that a query result is received identifying the maximumnumber of records, a plurality of queries generator 418 generates aplurality of queries based upon the initial query. Each of the pluralityof queries generated causes the query system to identify less than themaximum number of records deliverable by the query system. If one of theplurality of queries generated returns query results equal to themaximum number of records, those result are not used. The plurality ofqueries are generated to correspond to the scope or range of the initialquery. A record combiner 420 combines records identified by theplurality of queries into combined records. The record combiner may alsoeliminate duplicate records from the combined records resulting from anyoverlapping scope of each of the plurality of queries. A query responder422 is coupled to the initial query generator, the query respondertransmits a response to the initial query. Depending upon the initialquery, the response may comprise either records of the initial querybased on the initial query causing the query system to identify lessthan the maximum number of records, or the combined records based on theinitial query causing the query system to identify the maximum number ofrecords. The response may include either the identification of therecords or retrieve the records from the corresponding databasecorresponding to the identification.

In one example the initial query may have an initial range defined by aparameter such as a time stamp having a starting key value and an endingkey value. In this example, the plurality of queries generator mayfurther comprise a range processor 424 adapted to determine the initialrange and generate each of the plurality of queries with a range lessthan the initial range, wherein a combined range of each range of theplurality of queries corresponds to the initial range. In this examplethe scope of the initial query include records between January andDecember. If more than the maximum number of records deliverable by thequery system, then the range processor 424 may cause the plurality ofqueries generator 418 to generate two queries, a first having a range ofJanuary to April, and the second having a range of April to Decemberbased on the result of the initial query having an uneven or clustereddistribution. In this example, April may correspond to the median valueand the first and second queries have reduced ranges that cause thequery system to deliver less than the maximum number of recordsdeliverable by the query system for each of the plurality of queries.Thus the range of the first and second queries, when combined,correspond to the range of the initial query. Furthermore, since therange of both the first and the second queries include the month ofApril there is an overlap of ranges and duplicate records may bedelivered by both queries. In response, the record combiner 420eliminates duplicate records from the combined records resulting fromthe plurality of queries. While in this example, it may not be necessaryto have overlapping ranges, such as the month of April, in two queries,in other example ranges, such an overlap by be beneficial, includingsimplification in determining the starting key value and ending keyvalue each of the plurality of queries. For example, one of theplurality of queries has a first range having a first starting key valueand a first ending key value and another of the plurality of queries hasa second range having a second starting key value and a second endingkey value, the first ending key value being equivalent to the secondstarting key value. Thus, an offset or incremental difference betweenthe first ending key value and second starting key value need not bedetermined

FIG. 5 depicts an example flow diagram of a process operating in a queryprocessor for querying systems with limited capabilities. An initialquery is received at step 502, and step 504 selects at least one of aplurality of query systems based upon the initial query. Then step 506determines if a selected query system has a maximum number ofdeliverable records. This determination may be made by querying thequery system and storing the limitation of the query system, or thedetermination may be recalled from memory, or may be determined bymultiple queries. For example the results of an initial query having afirst range may return a first number of records. Based on the returnedrecords, the range may be reduce to produce one or more less records anda query of the reduced range submitted to the query system. If the samenumber or records are identified by the reduced range query, then thequery system has a maximum number or records corresponding to the numberof records returned. Any method of determining if a query system has amaximum number or records deliverable by the query system is within thescope of this disclosure.

Step 508 then transmits the query to the query system and step 510receives the results of the query. Step 512 determines if the resultsincludes the maximum number of records deliverable by the query system.If so then the query is modified at step 514 and transmitted at step508. Any type of query modification is included within the scope of thisdescription. An above example showed modification of a query having arange corresponding to a time stamp. Examples of other modificationsinclude ranges corresponding to alphabetical sequences, price sequences,location based sequences and other parameters known to those familiarwith the art.

If the number of records returned is less than the maximum at step 512,then step 516 determines if the combined queries have results less thanthe maximum number of results deliverable by the query system correspondto the initial query. For example if a query has a time stamp range, dothe combined time stamp ranges of the plurality of queries correspond tothe time stamp range of the initial query? If not, then a next of theplurality of queries is generated at step 518 and transmitted to thequery system at step 508.

If the combined plurality of queries correspond to the initial query atstep 516, then step 520 combines the results of the plurality of queriesreturning less than the maximum number of deliverable records of thequery system and step 522 eliminates duplicate records that may be theresult of overlapping scopes of the plurality of queries. Note that inanother example, step 522 may be performed after each acceptable queryof the plurality of queries. Then step 534 transmits the combinedrecords to the search generator as a response to the initial search.

The process of FIG. 5 has the advantage of providing a complete responseto an initial query even if the initial query results in a number ofrecords that exceeds the maximum number of records deliverable by thequery system. This is achieved by determining that the initial querycauses a query system to identify a maximum number of recordsdeliverable by the query system, and generating a plurality of queriesbased upon the initial query, each of the plurality of queries causingthe query system to identify less than the maximum number of recordsdeliverable by the query system, combining records identified by theplurality of queries into combined records; and transmitting thecombined records as a response to the initial query.

The process of FIG. 5 may result in an iterative or adaptive process ingenerating a query that does not cause the query system to identify themaximum number of records deliverable by the query system as evidencedby repeated execution of steps 508-514 until the number of records isless than the maximum at step 512, thereby contributing to the adaptivenature of the process of the present description. For example, theplurality of queries may generate a first query having a first rangeless than the initial range, and the record combiner combines recordsidentified by the first query based upon the first query causing thequery system to identify less than the maximum number of recordsdeliverable by the query system. However, if the first query causes thequery system to generate the maximum number of records deliverable bythe query system, then a subsequent execution of steps 508-514 generatesa second query having a second range less than the first range basedupon the first query causing the query system to identify the maximumnumber of records deliverable by the query system, in which case thecombining of step 516 does not combine records identified by the firstquery and does combine records identified by the second query based uponthe second query causing the query system to identify less than themaximum number of records deliverable by the query system. Thus, resultsof queries returning the maximum number of records deliverable by thequery system are not combined and results of queries returning less thanthe maximum number of records deliverable by the query system arecombined.

The process of FIG. 5 does not require every initial query to result inthe generation of a plurality of queries. In one example, the queryprocessor may receive another query, such as a new initial query forquery generator 402, determine that the other query causes the querysystem to identify less than the maximum number of records deliverableby the query system at step 512 and transmit records identified by theother query as a response to the other query at step 524. In thisexample, step 514 is not executed and the execution of step 520 and 522referring to query result combining and elimination record duplicationsare optional because a plurality of queries need not be generated.

FIG. 6 depicts an example flow diagram of a process for modifying aquery having a range. Step 602 corresponds to step 514 of FIG. 5 andprovides a more detailed description of modifying a query having arange. Step 604 determines the starting key value of the current queryand step 606 determines the median key value of keys of the currentquery. Then step 608 sets the ending key value of the modified query tothe median key value. This has the intended effect of generating a newquery having a range that is reduced by half of the current query. Thisstep is executed because the current query returned the maximum numberof records deliverable by the query system. The actual number of recordscorresponding to the current query is unknown and may be slightly morethan the query system's maximum or may be significantly more than thequery system's maximum number of deliverable records. Furthermore, themedian value is determined from the key values of the identifiedrecords, which does not include all of the records in the range of thecurrent query.

FIG. 7 depicts an example flow diagram of a process for determining amedian key value of a current query. Step 702 provides a more detailprocess of step 606 of FIG. 6. Step 704 selects a fraction of theidentified records, in this example one in ten records, and step 706sorts the selected records by key value. Then step 708 determines themedian value of the sorted records by determining the midpoint of thesorted records in a manner known to those familiar with the art.Experiments has shown that this approach is an efficient approach atdetermining a median value in that it finds a representative medianvalue with reduced intensive processing of the computer systemcalculating the median value.

While the process described above shows generating a plurality ofqueries based on an initial query and median values of query results,other approaches may be utilized for generating the plurality of querieswhile remaining within the scope of the description. For example, a newquery can be generated by arbitrarily reducing the range of a previousquery by a set amount, such as half. In another example, the magnitudeof a range of a subsequent query may be set to the magnitude of therange of a previous query that resulted in query system identifying lessthan the maximum number of records deliverable by the query system. Inanother example, if the database has a known characteristicdistribution, for example it may be known that more records exist withina first time range than in a second time range, then the range of theplurality of queries may be adjusted in response to the distribution.Also, the results of the adaptive process of a previous initial querycan be applied to a new initial query in the generation of the pluralityof queries.

III. Computer Program Process

The methods described herein may be implemented in a computer programproduct for processing a query, the computer program product comprisinga computer readable storage medium having program instructions embodiedtherewith. The program instructions may be executable by a computersystem to cause the computer system to perform the method.

The respective implementations of the present disclosure can be carriedout in any appropriate mode, including hardware, software or firmwarestored on a storage media and executed computer storage program product,or combination thereof. Alternatively, it is possible to at leastpartially carry out the implementation of the present disclosure ascomputer software executed on one or more data processors and/or adigital signal processor. The components and modules or processes of theimplementation of the present disclosure can be implemented physically,functionally and logically in any suitable manner. Indeed, the functioncan be realized in a single member or in a plurality of members, or as apart of other functional members. Thus, it is possible to implement theimplementation of the present disclosure in a single member ordistribute it physically and functionally between different members anda processor.

Computer program code for carrying out operations for aspects of thepresent disclosure may be written in any combination of one or moreprogramming languages, including an object oriented programming languagesuch as Java, Smalltalk, C++ or the like and conventional proceduralprogramming languages, such as the “C” programming language or similarprogramming languages. The program code may execute entirely on theuser's computer, partly on the user's computer, as a stand-alonesoftware package, partly on the user's computer and partly on a remotecomputer or entirely on the remote computer or server. In the latterscenario, the remote computer may be connected to the user's computerthrough any type of network, including a local area network (LAN) or awide area network (WAN), or the connection may be made to an externalcomputer (for example, through the Internet using an Internet ServiceProvider).

Aspects of the present disclosure are described herein with reference toflowchart illustrations, flow diagrams and/or block diagrams of methods,apparatus (systems) and computer program products according toimplementations of the disclosure. It will be understood that each blockof the flowchart illustrations and/or block diagrams, and combinationsof blocks in the flowchart illustrations and/or block diagrams, can beimplemented by computer program instructions. These computer programinstructions may be provided to a processor of a general purposecomputer, special purpose computer, or other programmable dataprocessing apparatus to produce a machine, such that the instructions,which execute via the computer or other programmable data processingapparatus, create means for implementing the functions/acts specified inthe blocks of the flowchart illustrations and/or block diagrams.

These computer program instructions may also be stored in a computerreadable medium that can direct a computer or other programmable dataprocessing apparatus to function in a particular manner, such that theinstructions stored in the computer readable medium produce an articleof manufacture including instruction means which implement thefunctions/acts specified in the blocks of the flowchart illustrationsand/or block diagrams.

The computer program instructions may also be loaded onto a computer orother programmable data processing apparatus to cause a series ofoperational steps to be performed on the computer or other programmabledata processing apparatus to produce a computer implemented process suchthat the instructions which execute on the computer or otherprogrammable apparatus provide processes for implementing thefunctions/acts specified in the blocks of the flowchart illustrationsand/or block diagrams.

The present disclosure is described by use of detailed illustration ofthe implementations of the present disclosure, and these implementationsare provided as examples and do not intend to limit the scope of thepresent disclosure. Although these implementations are described in thepresent disclosure, modifications and variations on theseimplementations will be apparent to those of ordinary skill in the art.Therefore, the above illustration of the exemplary implementations doesnot confine or restrict the present disclosure. Other changes,substitutions and modifications are also possible, without departingfrom the scope of the description and the appended claims.

What is claimed is:
 1. A method operating in a query processor, themethod comprising: receiving an initial query; determining that theinitial query causes a query system to identify a maximum number ofrecords deliverable by the query system; and generating a plurality ofqueries based upon the initial query, each of the plurality of queriescausing the query system to identify less than the maximum number ofrecords deliverable by the query system.
 2. The query processing methodaccording to claim 1 further comprising: combining records identified bythe plurality of queries into combined records; and transmitting thecombined records as a response to the initial query.
 3. The methodaccording to claim 2 further comprising: receiving another query;determining that the other query causes the query system to identifyless than the maximum number of records deliverable by the query system;and transmitting records identified by the other query as a response tothe other query.
 4. The method according to claim 2 wherein the initialquery has an initial range, and each of the plurality of queries has arange less than the initial range.
 5. The method according to claim 4wherein a combined range of each range of the plurality of queriescorresponds to the initial range.
 6. The method according to claim 4wherein the generating generates a first query having a first range lessthan the initial range, and the combining combines records identified bythe first query based upon the first query causing the query system toidentify less than the maximum number of records deliverable by thequery system.
 7. The method according to claim 6 wherein the generatinggenerates a second query having a second range less than the first rangebased upon the first query causing the query system to identify themaximum number of records deliverable by the query system, and thecombining does not combine records identified by the first query andcombines records identified by the second query based upon the secondquery causing the query system to identify less than the maximum numberof records deliverable by the query system.
 8. The method according toclaim 6 wherein the first range has a first starting key value and afirst ending key value, the generating generates a second query having asecond starting key value and a second ending key value, the secondstarting key value being equivalent to the first ending key value, andthe combining combines records identified by the first query and thesecond query based upon the second query causing the query system toidentify less than the maximum number of records deliverable by thequery system and eliminates duplicate records based upon the secondstarting key value being equivalent to the first ending key value. 9.The method according to claim 6 wherein the initial range is based upona starting key value and an ending key value and the method furthercomprises determining a median key value based upon records identifiedby the initial query, and further wherein the first range is based uponthe starting key value and the median key value.
 10. The methodaccording to claim 9 further wherein a fraction of the recordsidentified by the initial query are sampled in determining the mediankey value.
 11. The method according to claim 10 further wherein thefraction corresponds to one in ten the records identified by the initialquery and the query processor corresponds to a process operating in acloud computing environment.